1. Field of the Invention
The present invention relates to a waveform-data dividing device which is used to divide waveform data to registers so that the waveform data are stored by a waveform memory of an electronic musical instrument in connection with the registers.
2. Prior Art
The electronic musical instruments conventionally known employ waveform memories as sound sources. The waveform memory stores waveform data which are obtained by sampling sound waveforms. The electronic musical instrument of waveform-memory type has a tendency in which as the original pitch indicative of the waveform data becomes lower than the relative pitch indicative of the musical tone to be produced, each of intervals of time used for sampling the sound waveform becomes more rough, which eventually causes a problem that the quality of the musical tone to be produced will be deteriorated. On the other hand, if the musical tone is reproduced using a certain register whose pitch is higher than the original pitch, the electronic musical instrument suffers from another problem that when raising the relative pitch too high, high-frequency components, contained in the waveform data stored by the waveform memory, are somewhat folded back so that so-called "folded noises" (or "reflected noises") may occur.
Due to the above-mentioned reasons, the electronic musical instrument of the waveform-memory type is designed such that the overall frequency range, containing all of the pitches which are produced by the keyboard, is divided into multiple frequency ranges, which are called "registers", so that certain waveform data are stored by the waveform memory in connection with a certain register. Thus, the electronic musical instrument controls the relative pitch such that the relative pitch does not become too high or too low as compared to the original pitch.
Meanwhile, the electronic musical instrument of sampling-sound-source type is known as a "sampler". This sampler uses a random-access memory (i.e., RAM), whose data can be rewritten, as the waveform memory. Hereinafter, this RAM will be called a waveform RAM. The waveform data supplied by the external device or the like are written into the waveform RAM, so that the waveform RAM in which desired waveform data are written is used as the sound source by which desired musical tones are produced. Because of the reasons described before, the sampler is designed such that a specific register is set for the waveform data.
Specifically, the user of the sampler should manually set a specific tone pitch and a specific register on the waveform data before or after storing the waveform data. When the musical tone is produced directly using the waveform data read from the waveform RAM, a deviation frequently occurs between the pitch designated by the user and the pitch of the musical tone produced. Therefore, it is necessary for the user to manually correct or eliminate such deviation.
The above-mentioned register setting method conventionally employed by the sampler requires the user to manually input the pitch and register with respect to the waveform data stored by the waveform RAM. Such manual input operations are troublesome for the user.
Since the deviations in pitch should be successively sensed by the user so that the user is requested to correct them manually, the input operations become complicated and much time is required.